1. Field of the Invention
The present invention relates to an improvement in a process for the hydrogenation of aromatic hydrocarbons.
2. Description of the Prior Art
Hydrogenation processes in which aromatic compounds alone or contained in hydrocarbonaceous oils are hydrogenated in the presence of hydrogen and a suitable catalyst are known.
U.S. Pat. No. 3,655,551 discloses that Group VIII noble metals, such as palladium or platinum on zeolites, exhibit high hydrogenation activity such that if a substantially sulfur-free atmosphere is maintained, effective hydrogenation activity of aromatics can occur at 200.degree. to 500.degree. F., pressures of 500 to 3000 psig and a space velocity of 0.5 to 2.0 and those conditions can be correlated such that little or no cracking occurs.
U.S. Pat. No. 4,240,900 discloses pretreating hydrocracking catalysts with nitrogen-containing organic compounds to suppress the cracking activity and subsequently using the treated catalyst to hydrogenate olefins and aromatic compounds contained in a hydrocarbonaceous stream.
It has now been found that improved hydrogenation can be obtained by utilizing a pretreated catalyst that has been stripped with hydrogen after being treated with a nitrogen compound to suppress its cracking activity.